On this blog, I try to deal with issues related to Food as the main theme. But also Agriculture and the Environment.
On this blog I highly welcome comments, suggestion, contributions and questions to ensure that it becomes better and better by each day that passes.
Feel free to join as a member. I welcome members from all over the globe!
Contact E-mail: simplyhealthylifemagazine@gmail.com
I wish you all the best in enjoying the reading of “Simply Healthy Life Magazine”

About Me

Monday, 13 February 2012

Nitrates, Nitrites, Meat and Meat Products

Nitrates, Nitrites, Meat and Meat Products

Nitrates and Nitrites are
fundamental components of the global nitrogen cycle and are therefore found throughout
the environment. Nitrates and nitrites are compounds that contain a nitrogen
atom joined to oxygen atoms, with nitrate containing three oxygen atoms and
nitrite containing two. In nature, nitrates are readily converted to nitrites and
vice versa. Both are anions or ions with a negative charge. They tend to
associate with cations, or ions with a positive charge to achieve a neutral
charge balance. (Argonne National
Laboratory, 2005).

The role of Nitrates and Nitrites in Cured Meat
Products

Potassium and
sodium salts of the nitrate and nitrites are the most extensively used of all
food additives (Stevanovic and Šentjurc, 2000). Nitrates and nitrites in cured
meat and meat products play a multipurpose role; in addition to effectively
inhibiting the growth and toxicogenic effect of Clostridium botulinum, nitrite is responsible for the development
of typical cured-meat color and flavor, and also functions as an antioxidant
(Rincón et al., 2008), retarding the development of rancidity, off-odors and
off-flavors during storage, inhibiting the development of warmed-over flavor and
preserving flavors of spices and smoke (Zdzlaslaw, 2002).

Adding nitrite
to meat is only part of the curing process (Feiner, 2006). Ordinary table salt
(sodium chloride) is added because of its effect on flavor. Sugar is added
because of its contributions to flavor, browning during frying process and its
ability to disguise high levels of salt in a meat product. Spices and other
flavorings are often added to contribute to flavor, aroma and taste but not
added for nutritional purposes (Feiner, 2006).

Sodium nitrite,
rather than sodium nitrate, is the most commonly used for curing (although in
some products, such as country ham, sodium nitrate is used because of the long
aging period) (Stevanovic and Sentjuric, 2000). In a series of normal
reactions, nitrite is converted to nitric oxide (Fennema, 1996). Nitric oxide
combines with myoglobin, the pigment responsible for the natural red color of
uncured meat forming nitric oxide myoglobin, which is a deep red color (as in
uncooked dry sausage). This changes to the characteristic bright pink normally
associated with cured and smoked meat (such as wieners and ham) when heated
during the smoking process (Feiner, 2006).

When
sodium nitrite is added with the salt, the meat develops a red, then pink
color, which is associated with cured meats such as ham, bacon, hot dogs, and
bologna. Nitrite reacts with the meat myoglobin to cause these color changes,
first converting to the unstable nitrosomyoglobin (bright red), then on heating,
to a more stable nitrosohemochrome, a pink pigment (Zdzlaslaw, 2002; Fennema,
1996).

Modification of the myoglobin
molecule takes place in the meat curing process where nitric oxide (NO), which
originates from the sodium nitrite or potassium nitrite curing agent, combines
to form nitrosomyoglobin (Fennema, 1996).

According to Feiner (2006), this
reaction takes place at pH value below 6.5 and in meat products a pH value of a
round 4.7(salami) to 6.0 is present in the final product. When used, sodium
nitrate (NaNO3) does not contribute directly to the formation of the
red curing color but rather reduced to sodium nitrite (NaNO2) thus
providing nitric oxide (NO) by the reactions above, which results into the
formation of the characteristic pink cured meat color (Feiner 2006, Fidel,
et al, 2009). Examples such products are; ham, corned
beef, bacon, salami, and sausage.

In the presence of thiol compounds
as reducing agents in the reversible reaction, myoglobin may form a green
sulfmyoglobin (Zdzlaslaw,
2002). Other reducing agents, for example ascorbate
lead to formation of cholemyoglobin making the reaction irreversible (Fiener,
2006).

Animal
blood and its dehydrated protein extracts, which are mainly hemoglobin, are a
potential source of red and brown heme pigment which may be used as red and brown
coloring to meat products. However in most countries their usage as food
colorant is not permitted (Zdzlaslaw, 2002).

Meat, nitrates, nitrites and cancerColorectal cancer is the main cancer type that has been associated with
high meat consumption. Based on a considerable number of studies a 12–17%
increased risk of colorectal cancer was associated with a daily increase of 100
g of red meat and a 49% increased risk associated with a daily increase of 25 g
of processed meat (ferguson, 2010).Processed meats include sausages, smoked beef and hams among others in
which case nitrates and nitrites are used as additives.

Hill (1991) reported that the use of nitrites in cured meats experienced
a serious drawback in the late 1960s in the usa due to the n-nitrosamines
scare. The presence of some n-nitrosamines, as a consequence of the reaction of
nitrites with secondary amines especially in thermally treated cured meats,
caused a ban in the usa that was lifted after re-considering maximum amounts to
be added. A number of n-nitrosamines are potential carcinogenic agents and are
postulated to have several deleterious health effects, so their formation must
be prevented. According to stevanivic and senjurc (2002) and hill (1991), the
addition of ascorbic acid ensured the reaction of nitrite to nitric oxide and
thus reduced the possibility for the formation of n-nitroso compounds in meat
products. N-nitroso compounds are formed by the action of nitrous acid on a
suitable secondary nitrogen group. If the parent nitrogen group is a secondary
amine, then the product is an n-nitrosamine giving rise to n-nitrosamides,
ureas to n-nitrosoureas, all of which are carcinogenic to the body. The
n-nitrosamines are target organ specific and cause tumors at sites distant from
that of their introduction into the body. N-nitrosamide and n-nitrosoureas are
locally acting and cause tumors only at their sites of introduction. The
n-nitrosamines are not directly acting mutagens but need activation by
microsomal enzymes before they are mutagenic in the salmonella mutagenesis assay. They also need to be activated in the
body, but this process which leads to the organotropism of these compounds, is
little understood (hill 1991)

In reference to the above, it is
therefore necessary to develop alternatives to nitrates and nitrites.
Researchers have proposed different methods to inhibit the possibility of
N-nitrosamine formation in cured meat products. These include a decrease in the
level of added nitrite or the use of N-nitrosamine blocking agent such as
ascorbate and α- tocopherol (Stevanivic and Senjurc, 2002). However, as far as
N-nitrosamines are concerned, the most attractive and reliable method is total
elimination of nitrites and nitrates from the curing process. The alternative
of natural plant colorants extracted directly from plants or plant parts that
totally eliminate the use of nitrite from the curing process can be a viable alternative
for coloring comminuted meat as a substitute for nitrates, nitrites and
synthetic colorants to give the products their characteristic pink color.

Note that all references used in all postings related to the topic of sausages, meat and meat product colorings will be posted in the last article about this topic.

About the authorMr.
Sempiri Geoffery, the author of this article graduated from
Makerere University witha Bsc In
Food Science and Technology Degree in January, 2011.

Followers

Amaranth and Sweet potato Based Value Added products

Innovations in Jinja-Uganda

Youth Food Based Businesses During the Agricultural trade Show of july/2011 in JinJa

youtth food businesses

WELCOME TO SIMPLY HEALTHY LIFE MAGAZINE!

"There is no longer beauty except in the struggle. No more masterpieces without an aggressive character. Poetry must be a violent assault against the unknown forces in order to overcome them and prostrate them before men". Filippo Tommaso Marinetti